Create local symlink corresponding to remote github repo

https://stackoverflow.com/questions/15844542/git-symlink-reference-to-a-file-in-an-external-repository

$ git submodule add https://github.com/theHilikus/JRoboCom
$ ln -s JRoboCom/jrobocom-core/src/main/resources/logback.xml
$ git add .gitmodules logback.xml
$ git commit -m "add a symbolic link to logback.xml with the respective submodule"